1. Field of the Invention
The field of the invention is inhalers for dry powder inhalants or drugs.
2. Description of the Prior Art
Certain medicines may be taken in dry-powder form directly into the lungs by inhalation through the mouth or inspiration through the nose. This process allows the medicine to bypass the digestive system, and in some cases, allows smaller doses to be used to achieve the same desired results as orally ingested medicines. In other cases, it provides a delivery technique for medicines that display unacceptable side effects when taken by other methods.
Various known inhalers form mists or aerosols of liquid medicines or powdered medicines. However, these devices typically have various disadvantages, including lack of efficiency in delivering the medicine or drug; difficulties in loading and use; the need for repeated deep inhalation; non uniform dosing; caking of powdered medicines; and others.
While certain drugs, such as asthma drugs, may be taken several times daily, other drugs, including certain peptides or proteins are typically taken less frequently. Due to the delay in using these types of drugs, after they are removed from their packaging, providing a large number of doses within a single package is not desirable, as some doses may become unusable due to exposure to the environment. In addition, many drugs are susceptible to a short shelf life when removed from a foil storage pouch or other sealed container, even under nominal environmental conditions. These types of drugs must be used almost immediately after being exposed to the environment. Accordingly, there is a need for an inhaler for efficiently providing a prepackaged single dose of a powdered drug.
Ordinarily, with dry powder inhalers, it is difficult or impossible to insure that all powder of each dose is drawn out of the device. Consequently, especially with sticky or adhesive drugs, residual powder can tend to accumulate within the device. This accumulation of residual powder can adversely affect the operation of the device, result in inaccurate dose delivery, allow for bacterial growth within the device, and result in other adverse effects. Accordingly, there remains a need for a dry powder inhaler which overcomes the disadvantages of residual powder.
It is an object of the invention to provide such an improved dry powder inhaler.